docs: def missing_uniprot_mapping(self):
          """list: List of genes with no mapping to UniProt."""
          uniprot_missing = []
          for g in self.genes:
              ups = g.protein.filter_sequences(UniProtProp)
  
              no_sequence_file_available = True
              for u in ups:
                  if u.sequence_file or u.metadata_file:
                      no_sequence_file_available = False
                      break
              if no_sequence_file_available:
                  uniprot_missing.append(g.id)
  
          return list(set(uniprot_missing))